Abstract: Based on the monitoring data of water quality,sediment quality and aquaculture organisms quality in Sansha Bay mariculture area from 2009 to 2018,the comprehensive state of environmental quality in Sansha Bay mariculture area was evaluated according to the comprehensive index method of environmental quality.The results showed that the comprehensive environmental quality of Sansha Bay mariculture area was with a steady and rising trend in the past decade.In 2009,the environmental quality level was only passing,and the environmental quality requirements of the functional area could not be met in some time periods.From 2010 to 2012,it was better and could generally met the environmental quality requirements.Since 2013,it had been excellent meeting the environmental quality requirements,but in 2018,the comprehensive index of environmental quality decreased slightly.This trend was related to the development of aquaculture industry,harbor industry and marine environmental protection in Sansha Bay in recent years.Through analyzing and evaluating the comprehensive situation of environmental quality in Sansha Bay mariculture area in recent ten years,the change trend of aquaculture environment was grasped,which provided basis for environmental protection of fishery waters.